Present approaches to mechanized pattern recognition can be characterized in three general categories. One approach is the employment of multi-process mechanisms which are designed to simulate the human brain's own method of pattern recognition. Dr. Frank Rosenblatt was one of the first to employ such techniques. In 1959, under contract to the Office of Naval Research, he demonstrated a device which, while it had only sixty-four artificial "neurons", was able to recognize all of the characters of the alphabet, regardless of format or size. While the theory of multi-layered multi-functional and cross-coupled "perceptrons" pioneered by Rosenblatt has been widely developed since 1959, the complexity and expense of such systems has always limited their practical employment.
An alternative approach toward the problem of pattern recognition involves the employment of an "artificial" technique designed to deal with a specific problem on the basis of known determinative characteristics. Inherently, such an approach to the pattern recognition problem is limited to so-called dedicated systems for use in specific specialized applications. For example, dedicated systems are employed in such areas as robotics, pattern reading code converters such as bar code readers, voice actuated mechanisms and optical character readers.
The third approach toward pattern recognition consists essentially of generating a video image of the object to be recognized using, by way of example, a television camera, and processing that image by passing the composite video through a low pass filter to generate a relatively low frequency waveform corresponding to the video image. This waveform is then compared to similar waveforms in a data base on a point by point basis in order to obtain a match between a data base waveform of known parameters and the unknown waveform corresponding to the object to be recognized. The data base waveform is generated in the same manner as the unknown waveform. This comparison is done by a digital computer which, when it determines that a match has been made, outputs the identification information associated with the known waveform which has been associated with the unknown waveform and, hence, is an identification of the pattern to be recognized. Systems of this last variety are illustrated in my earlier patents, namely, U.S. Pat. Nos. 3,877,019 and 3,908,078 under which a number of commercial products are manufactured.
While the systems disclosed in my earlier patents provide an effective solution to the problem of non-specialized pattern recognition without the need for extensive information processing, the very simplicity of the system, which makes it so desirable, renders it unsuitable for solving a number of classic pattern recognition problems.